/*
 * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package javax.naming.ldap;

/**
 * This interface represents an LDAPv3 control as defined in
 * <A HREF="http://www.ietf.org/rfc/rfc2251.txt">RFC 2251</A>.
 * <p>
 * The LDAPv3 protocol uses controls to send and receive additional data
 * to affect the behavior of predefined operations.
 * Controls can be sent along with any LDAP operation to the server.
 * These are referred to as <em>request controls</em>. For example, a
 * "sort" control can be sent with an LDAP search operation to
 * request that the results be returned in a particular order.
 * Solicited and unsolicited controls can also be returned with
 * responses from the server. Such controls are referred to as
 * <em>response controls</em>. For example, an LDAP server might
 * define a special control to return change notifications.
 * <p>
 * This interface is used to represent both request and response controls.
 *
 * @author Rosanna Lee
 * @author Scott Seligman
 * @author Vincent Ryan
 * @see ControlFactory
 * @since 1.3
 */
public interface Control extends java.io.Serializable {

  /**
   * Indicates a critical control.
   * The value of this constant is <tt>true</tt>.
   */
  public static final boolean CRITICAL = true;

  /**
   * Indicates a non-critical control.
   * The value of this constant is <tt>false</tt>.
   */
  public static final boolean NONCRITICAL = false;

  /**
   * Retrieves the object identifier assigned for the LDAP control.
   *
   * @return The non-null object identifier string.
   */
  public String getID();

  /**
   * Determines the criticality of the LDAP control.
   * A critical control must not be ignored by the server.
   * In other words, if the server receives a critical control
   * that it does not support, regardless of whether the control
   * makes sense for the operation, the operation will not be performed
   * and an <tt>OperationNotSupportedException</tt> will be thrown.
   *
   * @return true if this control is critical; false otherwise.
   */
  public boolean isCritical();

  /**
   * Retrieves the ASN.1 BER encoded value of the LDAP control.
   * The result is the raw BER bytes including the tag and length of
   * the control's value. It does not include the controls OID or criticality.
   *
   * Null is returned if the value is absent.
   *
   * @return A possibly null byte array representing the ASN.1 BER encoded value of the LDAP
   * control.
   */
  public byte[] getEncodedValue();

  // static final long serialVersionUID = -591027748900004825L;
}
